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The pre big bang condition

  1. Mar 29, 2008 #1
    I am wondering what were the conditions before the big bang
     
  2. jcsd
  3. Mar 29, 2008 #2
    This is a meaningless question that we'll never know the answer to. What came before time? No one knows. What came before the creation of everything? No one knows.
     
  4. Mar 30, 2008 #3
    Last edited by a moderator: Apr 1, 2008
  5. Mar 30, 2008 #4
    And that's why it's meaningless. "Time" itself is the arrow, and you are trying to use the rules of time while detaching yourself from it. It just doesn't work.
     
  6. Mar 30, 2008 #5
    Im thinking time was not present before the big bang
     
  7. Mar 30, 2008 #6

    marcus

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    That's quantum cosmology. It is an active field of research, especially since 2005. Computer modeling. Many papers published in scientific journals. There are now several models that extend back in time before the beginning of expansion. Testing them to see which fits observations best will be an exciting job.

    There is no scientific reason to say this. The old (1915) model of spacetime breaks down at the beginning of expansion. But new models (especially since 2005) fit the observational data at least as well as the old classic model and do NOT break down.
    So in the old classic model time does not extend back before the start of expansion and in the new models it does. Scientifically speaking there is no reason to say it is a meaningless question. Far from it! It is a key question that must be resolved by testing models, extremely meaningful to the field of quantum cosmology.

    That is correct. Martin Bojowald's papers are among the most highly cited recent (since 2005) papers in quantum cosmology. His QC models go back before expansion and provide a mechanism for inflation. At the last world conference on General Relativity and Gravitation (GR18 in 2007) Bojowald was awarded a prize for his work.

    I like your name, I think that Gammaray Burst was the brightest so far. :wink:

    It may not work for you, Poop-Loops, but it works for today's scientists. Maybe you have philosophical or religious obstacles in your head that prevent it from working. According to the scientific method, if you have two models that fit the data equally well then you have to make new observations to test and decide empirically. You can't just arbitrarily decide one one or the other because it suits your preconceptions.

    Why?
     
  8. Mar 30, 2008 #7
    IM haveing trouble with totally accepting that time exist (present?) I cannot see that it has an instant of the present.but a speculative past-future.It does make sence that time would exist pre big bang if it exist now
     
  9. Mar 30, 2008 #8

    marcus

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    Hi pop, whether time exists at the PRESENT or not is a philosophical question that I guess you just have to deal with. If anyone wants to know about the current state of the field, as regards this question of before the start of expansion, try this link

    http://www.slac.stanford.edu/spires...+DATE+>+2003&FORMAT=www&SEQUENCE=citecount(d)

    These are papers published since 2003 in quantum cosmology. At the Stanford SLAC database. The papers labeled with the "quantum cosmology" keyword, that their search engine uses. There are about 400 papers, as I recall.

    They are ranked by citation count, with the most highly cited papers listed first. Some of these papers have been cited hundreds of times (referenced in other research papers because their results are considered important by other researchers.)

    The overwhelming majority of the highly cited papers treat time as going back before the start of expansion, in most the period before the start of expansion is a contracting phase.
     
    Last edited: Mar 30, 2008
  10. Mar 31, 2008 #9
    your thinking is better than mine-if we live in a phisical world-are we existing in a moment or nano sec- living in the future is phlosopical and in the past is -but -i may have been reading to many internet crack sites- but is plain existence during expansion phisical-are we at a point on the arrow of time? And a little father tommorrow- to all (I know IM missing something)
     
  11. Apr 1, 2008 #10
    Hello pop. Everything is apparently meaningless...yup...thats how it seems to be. Even if the universe was created for us...and we tried to understand it...there is still the absence of the ultimate meaning (or maybe I'm just incapable of seeing it, who knows). Anyways...interesting question; I would like to ask an additional question: Did time come with the Big Bang or was it already there??...actually...what the hell is time??
     
  12. Apr 1, 2008 #11

    ZapperZ

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    I will remind everyone once again that if your post involves purely speculative, unpublished, and unverified speculation, then it is in violation of the PF Guidelines and this thread may be locked or deleted. Furthermore, if your arguments contain very little physics, but rather philosophical arguments, then this thread will be moved to the Philosophy forum. If that's what you want, then that will be the fate of this thread. If you'd rather discuss the physics aspect of it, then confine it within that area.

    Zz.
     
  13. Apr 3, 2008 #12
    Quantum Loop Gravity touches this issue. Abhay Ashtekar and Martin Bojowald have released papers stating that according to loop quantum gravity, the problem of the singularity of the Big Bang is avoided. What the researchers found was a prior collapsing universe. Since gravity becomes repulsive near Planck density according to their simulations, this resulted in a Big Bounce and the birth of our current universe. These topics are an active research in loop quantum cosmology. although for now nobody knows for sure what was before the big bang
     
  14. Apr 3, 2008 #13
    Quantum Loop Gravity proposes a radical idea, it says that space and time may not be continuous but it claims that space comes in descrete small lumps called quantum of spacetime that are of the side of 10–99 cubic centimeter.

    This theory propose that time is created by the "move" that takes place on this quantum of spacetime.

    Time flows not like a river but like the ticking of a clock, with “ticks” that are about as long as the Planck time:10–43 second. Or, more precisely, time in our universe flows by the ticking of innumerable clocks in a sense, at every location in the spin foam where a quantum of spacetime “move” takes place, a clock at that location has ticked once.

    The difference in time from one tick to the next is approximately the Planck time, 10–43 second. "But time does not exist in between the ticks"; there is no “in between,” in the same way that there is no water in between two adjacent molecules of water.

    So perhaps time may not be continuous after all it may all just be a consequenze of having space.
     
  15. Apr 7, 2008 #14
    Well, we have indeed quantized just about everything else in this universe, so why not quantize time as well?!
     
  16. Apr 8, 2008 #15
    Time doesn't exist on its own but is part of the spacetime package (time is space just viewed in a different perspective - what some people see as time others travelling at different speeds see as space). Therefore, if there was no time before the big bang, there can't have been space either? And vice-versa, of course.
     
  17. Apr 19, 2008 #16
    I guess they will try to quantize the counciouness or the feelings as well in the future.:smile:
     
  18. Apr 24, 2008 #17
    Heh! Nice :biggrin:
     
  19. Apr 26, 2008 #18
    announcing the word time-may be same as announcing the word measurment-and simularly speaking the word meter -it is a mindset of a distance -but not necesserally any meaning of its own in a physical way-unless we apply one to it.We can announce 5 years time-but with the universe removed-5 years time would have no physical meaning.
     
  20. Apr 29, 2008 #19
    What was any (C_R?) manifold doing before Big Expansion of manifold? Can one have mass without a manifold description?
     
  21. May 5, 2008 #20
    One of the questions addressed by the String Vacuum Project is why string theory predicts [itex]10^{500}[/itex] distinct vaccua. A possible explanation is that each of these vacuua does indeed manifest itself, albeit in causally disconnected regions of spacetime.

    One model suggests that two branes collide with each other. For the moment think of these branes as two (huge) sheets of paper. The branes are not perfectly flat but are 'rippled'. When the branes collide they do not collide smoothly but the kinks and ripples strike first. The energy released by these ripples is enough to cause a big bang at each collision location on the brane, each with its own vacuua.

    So - to answer your question what happened before the big bang, (at least) two branes were on a collision course.

    Of course, this is not orthodox cosmology doctrine, but is being explored by a number of groups.
     
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